How to Create an Incremental Backup of a
UFS Snapshot (ufsdump)

Backing up a UFS snapshot incrementally means that only the files that
have been modified since the last snapshot are backed up. Use the ufsdump command with the N option. This option specifies
the file system device name to be inserted into the /etc/dumpdates file
for tracking incremental dumps.

The following ufsdump command specifies an embedded fssnap command to create an incremental backup of a file system.

In this example, the -o raw option is used to display
the name of the raw device instead of the block device. By using this option,
you make it easier to embed the fssnap command in commands
(such as the ufsdump command) that require the raw device
instead.